/* ==========================================
   MENU SYSTEM - Unified Navigation
   Mobile-first, Dark theme support
   ========================================== */

/* ==========================================
   CSS CUSTOM PROPERTIES (THEMING)
   ========================================== */

:root {
    /* Light theme (default) */
    --menu-bg-primary: #f9f9f9;
    --menu-bg-secondary: #ffffff;
    --menu-bg-tertiary: #f5f5f5;
    --menu-bg-hover: #e8e8e8;
    --menu-text-primary: #333333;
    --menu-text-secondary: #666666;
    --menu-text-muted: #999999;
    --menu-border-color: #dddddd;
    --menu-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
    --menu-overlay-color: rgba(0, 0, 0, 0.5);
    
    /* Shared accent colors */
    --menu-accent-primary: #ff6b00;
    --menu-accent-secondary: #0077c2;
    --menu-accent-success: #4caf50;
    --menu-accent-danger: #f44336;
    
    /* Transitions */
    --menu-transition-fast: 150ms ease;
    --menu-transition-normal: 250ms ease;
    --menu-transition-slow: 350ms ease;
    
    /* Spacing */
    --menu-spacing-xs: 4px;
    --menu-spacing-sm: 8px;
    --menu-spacing-md: 16px;
    --menu-spacing-lg: 24px;
    --menu-spacing-xl: 32px;
    
    /* Border radius */
    --menu-radius-sm: 4px;
    --menu-radius-md: 8px;
    --menu-radius-lg: 12px;
    
    /* Touch target minimum */
    --menu-touch-target: 44px;
}

[data-theme="dark"] {
    --menu-bg-primary: #1a1a2e;
    --menu-bg-secondary: #16213e;
    --menu-bg-tertiary: #0f3460;
    --menu-bg-hover: #1f4068;
    --menu-text-primary: #e8e8e8;
    --menu-text-secondary: #b8b8b8;
    --menu-text-muted: #888888;
    --menu-border-color: #3a3a5c;
    --menu-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    --menu-overlay-color: rgba(0, 0, 0, 0.7);
}

/* Reduce motion for accessibility */
@media (prefers-reduced-motion: reduce) {
    :root {
        --menu-transition-fast: 0ms;
        --menu-transition-normal: 0ms;
        --menu-transition-slow: 0ms;
    }
}

/* ==========================================
   UNIFIED HEADER
   ========================================== */

.unified-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--menu-spacing-sm) var(--menu-spacing-md);
    background-color: var(--menu-bg-secondary);
    border-bottom: 3px solid var(--menu-accent-primary);
    box-shadow: var(--menu-shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    min-height: 60px;
}

.header-left {
    display: flex;
    align-items: center;
    gap: var(--menu-spacing-sm);
    flex: 1;
    min-width: 0; /* Allow text truncation */
}

.header-flag {
    font-size: 24px;
    flex-shrink: 0;
}

.header-verb-selector {
    display: flex;
    flex-direction: column;
    min-width: 0;
    cursor: pointer;
    padding: var(--menu-spacing-xs) var(--menu-spacing-sm);
    border-radius: var(--menu-radius-md);
    transition: background-color var(--menu-transition-fast);
}

.header-verb-selector:hover,
.header-verb-selector:focus {
    background-color: var(--menu-bg-hover);
}

.header-verb-selector:focus {
    outline: 2px solid var(--menu-accent-secondary);
    outline-offset: 2px;
}

.header-verb-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--menu-text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    line-height: 1.3;
}

.header-verb-subtitle {
    font-size: 12px;
    color: var(--menu-text-muted);
    display: flex;
    align-items: center;
    gap: var(--menu-spacing-xs);
}

.header-verb-subtitle::before {
    content: "▼";
    font-size: 8px;
}

.header-right {
    display: flex;
    align-items: center;
    gap: var(--menu-spacing-xs);
    flex-shrink: 0;
}

/* Header buttons */
.header-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: var(--menu-touch-target);
    height: var(--menu-touch-target);
    background: none;
    border: none;
    border-radius: var(--menu-radius-md);
    cursor: pointer;
    color: var(--menu-text-secondary);
    font-size: 20px;
    transition: all var(--menu-transition-fast);
}

.header-btn:hover,
.header-btn:focus {
    background-color: var(--menu-bg-hover);
    color: var(--menu-text-primary);
}

.header-btn:focus {
    outline: 2px solid var(--menu-accent-secondary);
    outline-offset: 2px;
}

.header-btn:active {
    transform: scale(0.95);
}

/* Theme toggle icons */
.theme-icon-light,
.theme-icon-dark {
    display: none;
}

[data-theme="light"] .theme-icon-dark,
:root:not([data-theme]) .theme-icon-dark {
    display: block;
}

[data-theme="dark"] .theme-icon-light {
    display: block;
}

/* ==========================================
   MENU OVERLAY & CONTAINER
   ========================================== */

.menu-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--menu-overlay-color);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--menu-transition-normal), 
                visibility var(--menu-transition-normal);
}

.menu-overlay.is-open {
    opacity: 1;
    visibility: visible;
}

.menu-container {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: 85%;
    max-width: 320px;
    background-color: var(--menu-bg-secondary);
    box-shadow: var(--menu-shadow);
    transform: translateX(100%);
    transition: transform var(--menu-transition-normal);
    display: flex;
    flex-direction: column;
    z-index: 1001;
}

.menu-overlay.is-open .menu-container {
    transform: translateX(0);
}

/* Menu header */
.menu-header {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding: var(--menu-spacing-md);
    border-bottom: 1px solid var(--menu-border-color);
    min-height: 60px;
}

.menu-close-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: var(--menu-touch-target);
    height: var(--menu-touch-target);
    background: none;
    border: none;
    border-radius: var(--menu-radius-md);
    cursor: pointer;
    color: var(--menu-text-secondary);
    font-size: 24px;
    transition: all var(--menu-transition-fast);
}

.menu-close-btn:hover,
.menu-close-btn:focus {
    background-color: var(--menu-bg-hover);
    color: var(--menu-text-primary);
}

/* Menu navigation */
.menu-nav {
    flex: 1;
    overflow-y: auto;
    padding: var(--menu-spacing-sm) 0;
}

.menu-section {
    padding: var(--menu-spacing-sm) 0;
}

.menu-section:not(:last-child) {
    border-bottom: 1px solid var(--menu-border-color);
}

.menu-section-title {
    padding: var(--menu-spacing-sm) var(--menu-spacing-md);
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--menu-text-muted);
}

/* Menu items */
.menu-item {
    display: flex;
    align-items: center;
    width: 100%;
    min-height: var(--menu-touch-target);
    padding: var(--menu-spacing-sm) var(--menu-spacing-md);
    background: none;
    border: none;
    cursor: pointer;
    color: var(--menu-text-primary);
    font-size: 16px;
    text-align: left;
    text-decoration: none;
    transition: background-color var(--menu-transition-fast);
    gap: var(--menu-spacing-md);
}

.menu-item:hover,
.menu-item:focus {
    background-color: var(--menu-bg-hover);
}

.menu-item:focus {
    outline: none;
    box-shadow: inset 0 0 0 2px var(--menu-accent-secondary);
}

.menu-item.is-active {
    background-color: var(--menu-bg-tertiary);
    color: var(--menu-accent-secondary);
    font-weight: 600;
}

.menu-item-icon {
    font-size: 18px;
    width: 24px;
    text-align: center;
    flex-shrink: 0;
}

.menu-item-text {
    flex: 1;
}

.menu-item-arrow {
    color: var(--menu-text-muted);
    font-size: 12px;
    flex-shrink: 0;
}

.menu-item-value {
    color: var(--menu-text-muted);
    font-size: 14px;
    flex-shrink: 0;
}

/* ==========================================
   SUBMENU
   ========================================== */

.menu-submenu {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--menu-bg-secondary);
    transform: translateX(100%);
    transition: transform var(--menu-transition-normal);
    display: flex;
    flex-direction: column;
    z-index: 1;
}

.menu-submenu.is-open {
    transform: translateX(0);
}

.submenu-header {
    display: flex;
    align-items: center;
    padding: var(--menu-spacing-md);
    border-bottom: 1px solid var(--menu-border-color);
    min-height: 60px;
    gap: var(--menu-spacing-sm);
}

.submenu-back-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: var(--menu-touch-target);
    height: var(--menu-touch-target);
    background: none;
    border: none;
    border-radius: var(--menu-radius-md);
    cursor: pointer;
    color: var(--menu-text-secondary);
    font-size: 18px;
    transition: all var(--menu-transition-fast);
}

.submenu-back-btn:hover,
.submenu-back-btn:focus {
    background-color: var(--menu-bg-hover);
    color: var(--menu-text-primary);
}

.submenu-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--menu-text-primary);
    flex: 1;
}

.submenu-content {
    flex: 1;
    overflow-y: auto;
    padding: var(--menu-spacing-sm) 0;
}

/* Radio-style menu items */
.menu-item-radio {
    width: 20px;
    height: 20px;
    border: 2px solid var(--menu-border-color);
    border-radius: 50%;
    flex-shrink: 0;
    position: relative;
    transition: all var(--menu-transition-fast);
}

.menu-item.is-selected .menu-item-radio {
    border-color: var(--menu-accent-secondary);
    background-color: var(--menu-accent-secondary);
}

.menu-item.is-selected .menu-item-radio::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 8px;
    height: 8px;
    background-color: white;
    border-radius: 50%;
}

/* ==========================================
   VERB SELECTOR MODAL
   ========================================== */

.verb-modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--menu-overlay-color);
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--menu-transition-normal), 
                visibility var(--menu-transition-normal);
    display: flex;
    align-items: flex-start;
    justify-content: center;
    padding: var(--menu-spacing-lg);
    padding-top: 10vh;
    overflow-y: auto;
}

.verb-modal-overlay.is-open {
    opacity: 1;
    visibility: visible;
}

.verb-modal {
    width: 100%;
    max-width: 480px;
    max-height: 80vh;
    background-color: var(--menu-bg-secondary);
    border-radius: var(--menu-radius-lg);
    box-shadow: var(--menu-shadow);
    display: flex;
    flex-direction: column;
    transform: translateY(-20px);
    opacity: 0;
    transition: transform var(--menu-transition-normal),
                opacity var(--menu-transition-normal);
}

.verb-modal-overlay.is-open .verb-modal {
    transform: translateY(0);
    opacity: 1;
}

/* Modal header */
.verb-modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--menu-spacing-md);
    border-bottom: 1px solid var(--menu-border-color);
}

.verb-modal-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--menu-text-primary);
    margin: 0;
}

.verb-modal-close {
    display: flex;
    align-items: center;
    justify-content: center;
    width: var(--menu-touch-target);
    height: var(--menu-touch-target);
    background: none;
    border: none;
    border-radius: var(--menu-radius-md);
    cursor: pointer;
    color: var(--menu-text-secondary);
    font-size: 24px;
    transition: all var(--menu-transition-fast);
    margin: calc(var(--menu-spacing-md) * -1);
    margin-left: 0;
}

.verb-modal-close:hover,
.verb-modal-close:focus {
    background-color: var(--menu-bg-hover);
    color: var(--menu-text-primary);
}

/* Search input */
.verb-search-container {
    padding: var(--menu-spacing-md);
    border-bottom: 1px solid var(--menu-border-color);
}

.verb-search-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

/*
.verb-search-icon {
    position: absolute;
    left: 20px;
    color: var(--menu-text-muted);
    font-size: 16px;
    pointer-events: none;
} */

.verb-search-input {
    width: 100%;
    padding: 10px 12px 10px 40px;  /* Збільшення лівого paddingy для місця іконки */

    border: 2px solid var(--menu-border-color);
    border-radius: var(--menu-radius-md);
    background-color: var(--menu-bg-tertiary);
    color: var(--menu-text-primary);
    font-size: 16px;
    transition: border-color var(--menu-transition-fast);
}

.verb-search-input::placeholder {
    color: var(--menu-text-muted);
}

.verb-search-input:focus {
    outline: none;
    border-color: var(--menu-accent-secondary);
}

.verb-search-clear {
    position: absolute;
    right: var(--menu-spacing-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: none;
    border: none;
    border-radius: var(--menu-radius-sm);
    cursor: pointer;
    color: var(--menu-text-muted);
    font-size: 16px;
    opacity: 0;
    visibility: hidden;
    transition: all var(--menu-transition-fast);
}

.verb-search-clear.is-visible {
    opacity: 1;
    visibility: visible;
}

.verb-search-clear:hover {
    color: var(--menu-text-primary);
    background-color: var(--menu-bg-hover);
}

/* Recent verbs */
.verb-recent-section {
    padding: var(--menu-spacing-md);
    border-bottom: 1px solid var(--menu-border-color);
}

.verb-recent-section.is-hidden {
    display: none;
}

.verb-recent-title {
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--menu-text-muted);
    margin-bottom: var(--menu-spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--menu-spacing-xs);
}

.verb-recent-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--menu-spacing-sm);
}

.verb-recent-item {
    padding: var(--menu-spacing-xs) var(--menu-spacing-md);
    background-color: var(--menu-bg-tertiary);
    border: 1px solid var(--menu-border-color);
    border-radius: var(--menu-radius-lg);
    cursor: pointer;
    color: var(--menu-text-primary);
    font-size: 14px;
    transition: all var(--menu-transition-fast);
}

.verb-recent-item:hover,
.verb-recent-item:focus {
    background-color: var(--menu-accent-secondary);
    border-color: var(--menu-accent-secondary);
    color: white;
}

/* Verb list */
.verb-list-container {
    flex: 1;
    overflow-y: auto;
    padding: var(--menu-spacing-sm) 0;
}

.verb-list-section-title {
    position: sticky;
    top: 0;
    padding: var(--menu-spacing-sm) var(--menu-spacing-md);
    background-color: var(--menu-bg-tertiary);
    font-size: 14px;
    font-weight: 700;
    color: var(--menu-accent-primary);
    border-bottom: 1px solid var(--menu-border-color);
    z-index: 1;
}

.verb-list-item {
    display: flex;
    align-items: center;
    width: 100%;
    min-height: var(--menu-touch-target);
    padding: var(--menu-spacing-sm) var(--menu-spacing-md);
    background: none;
    border: none;
    cursor: pointer;
    color: var(--menu-text-primary);
    font-size: 16px;
    text-align: left;
    transition: background-color var(--menu-transition-fast);
}

.verb-list-item:hover,
.verb-list-item:focus {
    background-color: var(--menu-bg-hover);
}

.verb-list-item:focus {
    outline: none;
    box-shadow: inset 0 0 0 2px var(--menu-accent-secondary);
}

.verb-list-item.is-current {
    background-color: var(--menu-bg-tertiary);
    color: var(--menu-accent-secondary);
    font-weight: 600;
}

.verb-list-empty {
    padding: var(--menu-spacing-xl);
    text-align: center;
    color: var(--menu-text-muted);
}

/* Search results highlight */
.verb-list-item mark {
    background-color: rgba(255, 107, 0, 0.3);
    color: inherit;
    border-radius: 2px;
    padding: 0 2px;
}

[data-theme="dark"] .verb-list-item mark {
    background-color: rgba(255, 107, 0, 0.4);
}

/* ==========================================
   CONTENT SECTIONS (TABS REPLACEMENT)
   ========================================== */

.content-section {
    display: none;
    animation: fadeIn var(--menu-transition-normal);
}

.content-section.is-active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

/* ==========================================
   RESPONSIVE ADJUSTMENTS
   ========================================== */

@media (min-width: 768px) {
    .unified-header {
        padding: var(--menu-spacing-md) var(--menu-spacing-lg);
    }
    
    .header-verb-title {
        font-size: 22px;
    }
    
    .header-verb-subtitle {
        font-size: 13px;
    }
    
    .menu-container {
        max-width: 380px;
    }
    
    .verb-modal {
        max-width: 520px;
    }
}

/* ==========================================
   DARK THEME BODY STYLES
   ========================================== */

[data-theme="dark"] body {
    background-color: var(--menu-bg-primary);
    color: var(--menu-text-primary);
}

/* Integration with existing styles */
[data-theme="dark"] .container,
[data-theme="dark"] .verb-card,
[data-theme="dark"] .forms-section,
[data-theme="dark"] .exercise,
[data-theme="dark"] .tab-content {
    background-color: var(--menu-bg-secondary);
    border-color: var(--menu-border-color);
    color: var(--menu-text-primary);
}

[data-theme="dark"] table th {
    background-color: var(--menu-accent-secondary);
}

[data-theme="dark"] table td {
    border-color: var(--menu-border-color);
}

[data-theme="dark"] tr:nth-child(even) {
    background-color: var(--menu-bg-tertiary);
}

[data-theme="dark"] tr:hover {
    background-color: var(--menu-bg-hover);
}

[data-theme="dark"] input[type="text"],
[data-theme="dark"] select {
    background-color: var(--menu-bg-tertiary);
    border-color: var(--menu-border-color);
    color: var(--menu-text-primary);
}

[data-theme="dark"] input[type="text"]::placeholder {
    color: var(--menu-text-muted);
}

[data-theme="dark"] .result {
    background-color: var(--menu-bg-tertiary);
}

[data-theme="dark"] .correct {
    background-color: rgba(76, 175, 80, 0.2);
}

[data-theme="dark"] .incorrect {
    background-color: rgba(244, 67, 54, 0.2);
}

[data-theme="dark"] .infographics-legend,
[data-theme="dark"] .legend-item,
[data-theme="dark"] .checkbox-container {
    background-color: var(--menu-bg-tertiary);
    border-color: var(--menu-border-color);
}

[data-theme="dark"] .dialogue-text {
    background-color: var(--menu-bg-tertiary);
}

[data-theme="dark"] .dialogue-translation {
    background-color: var(--menu-bg-hover);
}

[data-theme="dark"] .spoiler-header {
    background-color: var(--menu-bg-tertiary);
    color: var(--menu-text-primary);
}

[data-theme="dark"] .spoiler-header:hover {
    background-color: var(--menu-bg-hover);
}

[data-theme="dark"] .example-item {
    border-color: var(--menu-border-color);
}

[data-theme="dark"] .context-examples-block {
    background-color: var(--menu-bg-tertiary);
    border-color: var(--menu-border-color);
}

[data-theme="dark"] footer {
    border-color: var(--menu-border-color);
    color: var(--menu-text-muted);
}

/* ==========================================
   UTILITY CLASSES
   ========================================== */

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}